1. Field of the Invention
This invention relates to a developer carrying member used in image-forming apparatus such as copying machines and printers that utilize electrophotography, a process for its production, and a developing assembly making use of the developer carrying member.
2. Description of the Related Art
In recent years, in order to meet a demand for making electrophotographic images higher in image quality, developers are being made smaller in particle diameter. Such developers having a small particle diameter come large in particle surface area per unit mass. Hence, the developers tend to come to have a large surface electric charge during the step of development. Meanwhile, in order to keep developers low consumable in quantity, spherical-particle developers have come to be used. Such developers have particle surfaces having been made smooth, compared with merely pulverized-particle developers, and tend to be electrostatically charged in excess to tend to result in an unstable charge quantity. As the result, they have a tendency to tend to cause faulty images such as sleeve ghost and density non-uniformity.
In Japanese Patent Application Laid-open No. H5-346727, a method is reported in which an iron complex compound is added to a surface layer of a developer carrying member so as to control the charge quantity of a developer.
In Japanese Patent Application Laid-open No. 2010-055072, a developer carrying member is disclosed which has a surface layer containing a specific quaternary phosphonium salt and a specific resin, and a method is reported by which developers made spherical-particle and negatively chargeable developers produced by polymerization are prevented from any excess charging such as charge-up.